Podlove Subscribe Button JS error


the podlove subscription button is not showing the services anymore? I get the following error in the console:

 Uncaught TypeError: Cannot read property 'replace' of undefined
    at e.prepareClients (app.js:1)
    at new e (app.js:1)
    at t.initPanels (app.js:2)
    at new t (app.js:1)
    at t.openPopup (app.js:1)
    at t.openPopup (app.js:1)
    at HTMLLIElement.<anonymous> (app.js:1)
    at HTMLLIElement.r.proxy (app.js:5)
e.prepareClients @ app.js:1
e @ app.js:1
t.initPanels @ app.js:2
t @ app.js:1
t.openPopup @ app.js:1
(anonymous) @ app.js:1
(anonymous) @ app.js:1
r.proxy @ app.js:5

I am setting up the site with https …
I also used the shortcode to generate the subscription button…


… somehow I deleted the feed URL … entered it again in the Podlover Subscription Button Setup and it works again…